Architecture Map

Budgeti backend follows a layered architecture where each layer has clear ownership:

• Product context: Budgeti is a mobile-first finance app with AI-assisted capture.
• Documentation scope here: backend implementation map for the currently ready component.

Layer map

• Presentation: Express routes, controllers, and HTTP middlewares.
• Application: use-case orchestration and service ports.
• Domain: entities, invariants, and repository interfaces.
• Infrastructure: Prisma repositories, external service adapters, logging.
• Shared: cross-cutting errors, schemas, types, and utilities.

Request path example

POST /api/v1/wallet flows through these files:

1. backend/src/Presentation/Routes/WalletRoutes.ts
2. backend/src/Presentation/Controllers/WalletController.ts
3. backend/src/Application/UseCases/Wallet/CreateWalletImpl.ts
4. backend/src/Infrastructure/Repositories/Prisma/WalletRepositoryImpl.ts

Composition root

• All bindings live in backend/src/Containers/inversify.config.ts.
• Symbol registry is declared in backend/src/Containers/Types.ts.

Error and response model

• Canonical error definition and status map: backend/src/Shared/Errors.ts.
• Error serialization middleware: backend/src/Presentation/Middlewares/errorsMiddleware.ts.

Health and readiness

• Lightweight liveness endpoint: GET /health in backend/src/app.ts.